1. Field of the Invention
This invention relates generally to a pneumoperitoneum needle for introducing gaseous fluids into a peritoneal cavity. More particularly, this invention is directed to a pneumoperitoneum needle featuring a built-in gas filtration unit.
2. Description of the Prior Art
Laparoscopic and endoscopic surgery has been widely accepted as the preferred surgical procedure for treatment of a variety of disorders that were formally treated with conventional surgical techniques.
In laparoscopic procedures, surgery is performed in the interior of the abdomen through a small incision; in endoscopic procedures, surgery is performed in any hollow viscus of the body through narrow endoscopic tubes inserted through small entrance wounds in the skin.
In conjunction with laparoscopic surgery, pneumoperitoneum gases are generally introduced into the peritoneal cavity to expand the cavity and raise the cavity wall away from the vital organs therein. Thereafter, a trocar, which is a sharp pointed instrument, is inserted into a cannula assembly and used to puncture the inner lining of the peritoneal cavity. The trocar is withdrawn and a laparoscopic surgical instrument is inserted through the cannula to perform the desired surgery.
A conventional system used for introducing the pneumoperitoneum gases into the peritoneal cavity includes a gas source or chamber and a pneumoperitoneum needle connected to the gas source via a flexible conduit. The pneumoperitoneum needle typically employed is a Veress-type needle which includes an elongated hollow outer sheath with a sharpened distal end for penetrating the inner lining of the peritoneal cavity. A spring-loaded blunt stylet is axially movable within the sheath and is distally biased so that the blunt end of the stylet extends beyond the sharp end of the needle once the needle penetrates the inner lining of the peritoneal cavity.
The pneumoperitoneum gas administering system also typically includes at least one volume flow regulator to control the rate of gas flow through the needle and a filtration unit to remove foreign matter from the gas such as water droplets or metal fragments inadvertently expelled from the gas source. The filtration unit is typically positioned between the gas source and the needle and is preferably replaced after a minimal number of uses.
A growing sentiment amongst medical personnel is that in order to provide optimal filtration of the pneumoperitoneum gases introduced into the peritoneal cavity and to adequately protect the patient from potential microbial contamination, the filtration unit should be replaced after a minimal number of uses, especially when CO.sub.2 gas is used as the insufflating agent. However, with the administering systems known heretofore, the potential for non-replacement of the filtration unit remains relatively high since the filtration unit is an independently maintained component in the gas administering system whose replacement is usually dependent upon the judgment of a medical technician. Consequently, there exists the possibility that a clogged, inactivated or poorly effective filter may be used.
Therefore, it would be desirable to ensure replacement of a filter in a gas administering system after each use. The present invention addresses this need by providing a disposable pneumoperitoneum needle which includes a built-in filtration unit. Thus, after a laparoscopic procedure, the needle is disposed of along with the housed filtration unit, thereby insuring that a new filter is used in a subsequent procedure.